Cadillac: On Board Diagnostics, cadillac dealership, cadillac sedan deville

Question
My parents own an 1991 Cadillac Sedan Deville with abt 80K miles. He has a standard instrument cluster, with digital fuel minder, and digital Electric Climate Control (ECC). On a recent trip, the "check engine soon" and "service engine soon" lights came on. Also, his temp light came on. The lights came on and off, and his fuel minder and ECC went out. He was concerned that the vehicle was overheating. We determined that the cooling fans were coming on. We bought a Haynes guide, and tried to find out how to access the On Board Diagnostics (OBD). During the procedure, we received "symbol" that looked like a lower case "d". We could find no reference to this code in the Haynes. Also, even when the iginition is off, the blower fan would run on occasion, up to several minutes after it is switched off. We asked the Cadillac dealership in Reno, NV, and they had never heard of the code either. The service person said it probably wasn't a severe engine problem, and said it was good we'd determined the fans were operating. But, my parents still cannot use the climate control, and have no idea how much fuel remains in the car when they drive after fill-up. They keep the tank topped off.

They live in Wyoming, and winter is approaching. They will need to get this fixed. They took the vehicle to the local dealership, and they sat on the car for 4 days without looking at it. They needed the vehicle back!

Have you ever encountered this "d" code before? It appears in both the digital fuel minder gauge, and the ECC. Is it possible the control panels (one or both) for the fuel minder or the ECC are  defective or need replacing. Any idea of cost for these? Any help you can afford would be greatly appreciated! Thanks!

Answer
Yes, I have seen this "d" many many times.

What you need to do is to replace the BCM computer. A very simple task.

You will need to contact me at:


 onlineautohelp@msn.com


In order for me to provide you with pictures, Instructions and electrical schematics (pictures).

PLEASE include your original question(s) and the MAKE-MODEL-YEAR and ENGINE SIZE of your vehicle when you contact me.

PLEASE tell me if you do your own repairs and or your skill level of auto repair. This is VERY VERY important if I am to be able to help you repair your own vehicle.